Relations between audiometrical thresholds of potential cochlear implant patients and their performance in preoperative psycho-physical tests with electrical stimulation.

Part of our selection procedure for cochlear implant candidates is the preoperative electrical stimulation of the cochlea. With a transtympanic needle, placed as closely as possible to the round window, the dynamic range for a number of frequencies is measured and a frequency identification test and a temporal difference limen test are carried out. Our first series of preoperative tests suggests a relationship between the audiometrical pure-tone thresholds, the dynamic range of electrical stimulation and the performance on the temporal difference and frequency identification test. For the preoperative electrical stimulation tests, a relatively good pure-tone average may indicate a wide dynamic range, a short temporal difference limen and a high score in the frequency identification test.